His son Georg Herbert converted the monastery building into a palace between 1846 and 1848 with the help of the Hanoverian architect Georg Ludwig Friedrich Laves. During renovations and new construction, the buildings were given an architectural appearance in the English Tudor Gothic style, which was unusual in Lower Saxony.
During World War II, the castle housed a Wehrmacht military hospital, and after the war, a military hospital for the British Rhine Army. Later, like in many other castles, a refugee camp was set up here.
There is an English landscape garden around the castle. After 2020 the gardens were transformed into a biopark. Wild flowers have been sown and the green areas are only trimmed every few months.
At the moment, the castle is home to a rather large museum of modern art, a boutique hotel and a restaurant are planned. The museum is open from around the beginning of March to the end of October, see the official website for information. Entrance to both the park and the museum is paid.
Getting there: parking lot 52.094722, 10.133556. Derneburg(Han) train station is 1.2 km from the castle, you can walk or take bus 34 towards Hildesheim to the Derneburg Kastanienallee stop.